Re: Good - Better - Best in HDMI cables.
I certainly see what you mean about not taking any chances with cables installed behind dry wall, especially long ones. (When we recently switched from cable to satellite, we had to replace our in-wall RG-59 with RG-6 -- not a fun experience!)
My initial point was just that any digital cable that is working properly (i.e. transmitting the ones and zeros accurately) will be indistinguishable from any other in terms of picture quality, etc. Therefore, it makes no sense whatsoever to speak of "high-end" cables vs. "mid-level" vs. "lower-end", as if there were a range of performance levels to meet the varying needs of consumers with differing demands for "quality".
Generally speaking a faulty cable should be readily noticeable, though, as noted by Lotus, there may be a picture, just with lost packets of pixels or other artifacts. I also agree with Lotus' point that name brand, more expensive cables, are not necessarily less likely to be faulty.
Furthermore, retailers have exorbitant markups on cables and routinely employ a lot of marketing misinformation to justify their ridiculous prices. (Analog cables, on the other hand, do have varying degrees of performance, though I am sure there is a lot of exaggerated misinformation in the marketing of these, as well.)
Just my $.02.